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The DQ88CX is one of a family of digital quad units recently announced by US manufacturer GYYR. The model weíre looking at is the PAL colour specification version, with 8 camera inputs and a two-page quad display.


The unit is housed in a black slim-line case measuring 43.8 x 19.21 x 5.1mm. On the front panel thereís a row of touch-sensitive switches with 14 clearly defined buttons. From left to right, the first one calls up the main on-screen display menu; next to that are four arrow or cursor buttons, for selecting and setting menu options. The next four buttons are for the eight camera inputs, each one switches between two inputs, these have LED indicators to show which one has been selected. Camera inputs are free-running, synchronisation is carried out internally though thereís a an option for line-locked cameras. The fifth button in this group steps through the two four-segment quad display pages. The remaining four buttons are for enabling the camera sequencer, selecting record mode, digitally enlarging a full-screen display by a factor of x2, and replaying a recording from a connected VCR.


The back panel is equally straightforward. There are eight BNC sockets, for each camera input, these are configured for CVBS (composite) video signals, there is no provision for Y/C camera inputs. A miniature 8-way switch between the first and second group of camera sockets sets the video termination for each input (75 ohm or Hi Z). The next four BNC sockets are for VCR input, monitor 1 and 2, and VCR outputs. On the right side thereís a bank of spring-loaded contacts for alarm inputs and outputs, a 9-pin D-socket for an RS-232 interface, and lastly the 12 volt DC input from the external mains PSU.


The standard of construction is very high. The main glass-fibre PCB is populated almost entirely by surface mounted components. The board also supports all of the units input and output sockets. A short ribbon cable links the main board to the front-panel buttons, apart from that thereís no other internal wiring, which should help maintain the unitís long-term reliability. The only quibble concerns the DC power plug and socket. Itís non-polarised, though the unit doesnít appear to mind which way round itís inserted, but it isnít held very securely and can easily become disconnected, if the wiring is disturbed.



The operating instructions are fairly brief, they contain all the necessary information for an experienced installer, but some of the operations are not terribly well explained and can take some time to decipher. More detailed explanations and/or a few extra diagrams would have been helpful  


The menu-driven on-screen display, selected by the Program button, has seven main options. The first two -- Quad A and Quad B -- are concerned with camera assignments to each of the two quad displays. A single camera input can appear on more than one quad segment or channel if required; unused channels appear blank. The Play menu covers monitor configuration whilst the unit is in VCR playback mode, this includes an option to enable a sequenced display of all connected cameras on quad channel 1 (top left hand corner of display), whilst the other three quadrants remain fixed. The Record menu deals with monitor assignment when the unit is in record mode. Monitor 1 output is intended for a floor display and can show either a full screen or quad display; the second monitor output is for the security room, this can show live full-screen or quad displays, or tape playback, with the facility to enlarge the centre portion of the image.


The fifth menu covers the display options. This includes sub-menus for setting the sequence rates for the display sequence (from 0.5 to 30 seconds), plus alarm and hold functions, configuring external control modes (by PC, via the RS232 interface), and changing the position of camera idents or titles on full-screen displays. Camera idents are set using the Title menu, each camera input can show one line of up to 9 characters, these are selected using the four cursor buttons. Lastly thereís the alarm menu, which toggles each of the 8 alarm inputs between normally open or normally closed.   


Following any alterations the display gives the user the option to save the changes to the units non-volatile memory. This has a battery backup, to prevent data loss in the event of a power interruption.  


When an alarm input is activated the alarm output (pin 3) goes high, and the monitor will display either a quad screen, full screen or freeze frame, depending on the chosen configuration, and selected alarm hold/freeze time (1 second to 15 minutes).


The external control function, via the RS232 interface to the serial communication port on a PC, enables remote selection (using standard comms software) of display format and camera input, plus alarm reports. Unauthorised alteration or tampering with the set-up can be prevented with a control lock function, and all settings can be returned to factory defaults using a simple sequence of key presses.



In the full-screen display mode video signals pass cleanly through the unit with no noticeable loss of definition or increase in noise. Quad displays also appear sharp, the images are stable with accurate, well-defined colours and no visible artefacts. In fact the only indication of the digital processing taking place, is a very short delay in the picture, amounting to no more than few milliseconds.



Clearly a lot of thought has gone into the design and manufacture of the DQ88CX. The two-page quad display is a very useful option, both from the point of view of installations using the full compliment of up to 8 cameras, and simpler set-ups, that may need to be expanded at a later date, without recourse to costly upgrades or replacement. Video performance is excellent, the extensive digital processing has negligible impact on picture quality. The system is very flexible and can accommodate a wide range of standard components, with the exception of cameras with Y/C outputs. Operationally it is moderately easy to set up though some functions can be a little cumbersome. Nevertheless once configured it should pose few problems for end-users.   



Design and design features              ****

Circuitry and components                  ****

Ease of installation and wiring    ****      

Range and variety of functions            ****     

Accompanying instructions                   **         

Technical advice and backup      

Value for money                         ****                            



R.Maybury 1995 2108




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